// Hex JavaScript decoder
// Copyright (c) 2008-2018 Lapo Luchini <lapo@lapo.it>

// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
// 
// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

(function (undefined) {
    "use strict";
    
    var Hex = {},
        decoder;
    
    Hex.decode = function(a) {
        var i;
        if (decoder === undefined) {
            var hex = "0123456789ABCDEF",
                ignore = " \f\n\r\t\u00A0\u2028\u2029";
            decoder = [];
            for (i = 0; i < 16; ++i)
                decoder[hex.charAt(i)] = i;
            hex = hex.toLowerCase();
            for (i = 10; i < 16; ++i)
                decoder[hex.charAt(i)] = i;
            for (i = 0; i < ignore.length; ++i)
                decoder[ignore.charAt(i)] = -1;
        }
        var out = [],
            bits = 0,
            char_count = 0;
        for (i = 0; i < a.length; ++i) {
            var c = a.charAt(i);
            if (c == '=')
                break;
            c = decoder[c];
            if (c == -1)
                continue;
            if (c === undefined)
                throw 'Illegal character at offset ' + i;
            bits |= c;
            if (++char_count >= 2) {
                out[out.length] = bits;
                bits = 0;
                char_count = 0;
            } else {
                bits <<= 4;
            }
        }
        if (char_count)
            throw "Hex encoding incomplete: 4 bits missing";
        return out;
    };
    
    // export globals
    if (typeof module !== 'undefined') { module.exports = Hex; } else { window.Hex = Hex; }
    })();
    